Semiconductor Device and Method of Manufacturing the Same

ABSTRACT

A semiconductor device having a semiconductor element (a thin film transistor, a thin film diode, a photoelectric conversion element of silicon PIN junction, or a silicon resistor element) which is light-weight, flexible (bendable), and thin as a whole is provided as well as a method of manufacturing the semiconductor device. In the present invention, the element is not formed on a plastic film. Instead, a flat board such as a substrate is used as a form, the space between the substrate (third substrate ( 17 )) and a layer including the element (peeled layer ( 13 )) is filled with coagulant (typically an adhesive) that serves as a second bonding member ( 16 ), and the substrate used as a form (third substrate ( 17 )) is peeled off after the adhesive is coagulated to hold the layer including the element (peeled layer ( 13 )) by the coagulated adhesive (second bonding member ( 16 )) alone. In this way, the present invention achieves thinning of the film and reduction in weight.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device having a circuitconsisted of a thin film transistor (hereinafter, referred to as TFT)and a method of manufacturing the semiconductor device. For example, thepresent invention relates to an electro-optic device that is representedby a liquid crystal module, a light emitting device that is representedby an electroluminescence display device and an electronic device onwhich such a device is mounted as a part.

It should be noted that in the present specification, the term“semiconductor device” indicates a device in general capable offunctioning by utilizing the semiconductor characteristics, and anelectro-optic device, a light emitting device, a semiconductor circuitand an electronic equipment are all semiconductor devices.

2. Related Art

In recent years, a technology constituting a thin film transistor (TFT)using a semiconductor thin film (in the range from about a few nm to afew hundreds nm in thickness) formed on the substrate having aninsulating surface has drawn attention. A thin film transistor is widelyapplied to electronic devices such as an IC, an electro-optic device orthe like, and particularly, there is an urgent need to be developed as aswitching element for an image display device.

Although as for applications utilizing such an image display device, avariety of applications are expected, particularly, its utilization forportable apparatuses has drawn the attention. At present, although manyglass substrates and quartz substrates are utilized, there are defaultsof being easily cracked and heavy. Moreover, the glass substrates andquartz substrates are difficult to be made larger in terms of conductinga mass-production, and these are not suitable for that. Therefore, theattempt that a TFT element is formed on a substrate having flexibility,representatively, on a flexible plastic film has been performed.

However, since the heat resistance of a plastic film is low, it cannothelp lowering the highest temperature of the process: As a result, atpresent, a TFT is formed which has not so excellent electriccharacteristics compared with those formed on the glass substrates.Therefore, a liquid crystal display device and light emitting elementhaving a high performance by utilizing a plastic film have not beenrealized yet.

If a liquid crystal display device or a light emitting device having anorganic light emitting device (OLED) can be formed over a flexiblesubstrate such as a plastic film, it can be obtained as a thinlight-weight device and can be used in a display having a curvedsurface, a show window, etc. Use of such a device is not limited to useas a portable device, and the range of uses of such a device is markedlywide.

Moreover, since the transparency of plastic film to the light is lowerthan that of glass substrate, it is not based on the quality of thematerial and thickness of a plastic film which pass light, but there isalso a problem that the transparency become worse slightly.

SUMMARY OF THE INVENTION

An object of the present invention is to provide the semiconductorequipment which is formed by semiconductor elements having thin filmthickness, a light-weight and flexible (curving is possible) (thin filmtransistor, a memory element, a thin film diode, the photoelectricconversion element and silicon resistance element that consists of PINjunction of silicone), and its production method.

In the present invention, the element is not formed on a plastic film.Instead, the present invention is characterized in that a flat boardlike a substrate is used as a form, the space between the substrate anda layer including the element is filled with coagulant (typically anadhesive), and the substrate used as a form is peeled off after theadhesive is coagulated to hold the layer including the element by thecoagulated adhesive (bonding member) alone. The bonding member adheresstrongly to the layer including the element.

According to a structure of the present invention disclosed in thisspecification, there is provided a semiconductor device characterized inthat a bonding member serves as a supporter and an element is formed onan insulating film that is in contact with the bonding member.

In the above-mentioned structure, the element is a thin film transistor,a light emitting element having an OLED, an element with liquid crystal,a memory element, a thin film diode, a photoelectric conversion elementof silicon PIN junction, or a silicon resistor element.

The thickness of the bonding member can be set appropriately. If thebonding member is thinner than the plastic film, the semiconductordevice can be thinner, more light-weight, and more flexible. When thebonding member alone holds the layer including the element, the totalthickness can be 0.5 mm or less, preferably 0.1 mm to 0.3 mm or less,for example.

The material of the bonding member can be chosen appropriately. Forexample, a thermally-curable material, a photosensitive material, or alight-transmissive material can be used for the bonding member. Whenlight from a light emitting element of a light emitting display deviceis to pass through the bonding member, the amount of light that passescan be large and therefore the luminance can be raised. A bonding memberthat can serve as a barrier by blocking permeation of moisture andoxygen from the outside is desirable for a light emitting device havingan OLED since the device is weak against moisture and oxygen.

It is preferable to choose a bonding member that is highly transmissiveof light for a transmissive liquid crystal display device if light fromthe backlight is to pass through the bonding member. The amount of lightthat passes can be increased by making the bonding member thinner thanthe plastic film.

Compared to the case where plastic films bonded by a bonding member areused, the present invention can raise the usability of light to improvethe luminance and increase the amount of light that passes. This isbecause the present invention allows light to be diffracted only at theinterface between the air and the bonding member by using a supporterthat consists solely of the bonding member instead of causing lightdiffraction at the interface between the air and the plastic film andthe interface between the plastic film and the bonding member both dueto difference in refractive index (although it also depends onmaterial).

In the above structure, a protective film may be formed in contact withthe bonding member.

In the above structure, the semiconductor device is characterized inthat the bonding member is pasted on a flat face or curved face basemember, and a thin and light-weight semiconductor device can beobtained. Examples of this semiconductor device include video cameras,digital cameras, goggle type displays, indicators for automobiles andmachines (such as a car navigation system and a speed meter), personalcomputers, and portable information terminals. To paste the bondingmember and the base member together, the same material as the bondingmember may be used or a different adhesive may be used. The bondingmember may be pasted on the base member by pasting the bonding member ona plastic film and then pasting the plastic film on the base member.

A process of obtaining the above structure is also one of aspects of thepresent invention. The process is characterized by having: forming on afirst substrate a layer to be peeled that includes a semiconductorelement; bonding a second substrate to the layer to be peeled using afirst bonding member; peeling the first substrate off; bonding a thirdsubstrate to the peeled layer using a second bonding member to sandwichthe peeled layer between the second substrate and the third substrate;peeling the second substrate off by removing the first bonding memberwith a solvent or by lowering the adhesion of the first bonding memberwith light (ultraviolet light, laser light, or the like); and peelingthe third substrate off. Namely, an aspect of the present inventiondisclosed in this specification relates to a method of manufacturing asemiconductor device, including, a first step of forming on a firstsubstrate a layer to be peeled that includes a semiconductor element, asecond step of bonding a second substrate to the layer to be peeledusing a first bonding member to sandwich the layer to be peeled betweenthe first substrate and the second substrate, a third step of separatingthe first substrate from the layer to be peeled, a fourth step ofbonding a third substrate to the peeled layer using a second bondingmember to sandwich the peeled layer between the second substrate and thethird substrate, a fifth step of separating the second substrate fromthe peeled layer and separating the third substrate from the secondbonding member to form the peeled layer that uses the second bondingmember as a supporter.

In the above fifth step, the second substrate and the third substrateare both separated from the peeled layer in the same step. Apparently,the second substrate and the third substrate may be separated indifferent steps and which of them is separated first is not fixed.

The first bonding member is made of a material that can be removed orreduced in adhesion by a solvent or light. The second bonding member mayhave a different composition than the first bonding member.

The present invention is characterized in that the second bonding memberadheres to the peeled layer at a stronger adhesion than its adhesion tothe third substrate in order to peel the third substrate off. Therefore,in order to lower the adhesion of the second bonding member to the thirdsubstrate, a glass substrate, a quartz substrate, or a metal substrateis used for the first substrate and the second substrate whereas aplastic substrate is used for the third substrate. Alternatively, thethird substrate may be a plastic film with an AlN_(X)O_(Y) film formedon its surface in order to lower the adhesion of the second bondingmember to the third substrate. The second bonding member is solidifiedwhile it is in contact with the third substrate. Therefore one side ofthe second bonding member is flat and the other side of the secondbonding member is closely fit to the peeled layer.

The second bonding member thus serves as a supporter ultimately.Therefore the total thickness as well as the total weight of the devicein the present invention can be smaller than in the case where a plasticsubstrate is used as a supporter.

The peeled layer refers to a layer including a semiconductor element.The peeled layer is a layer including one or more elements selected fromthe group consisting of a thin film transistor, a light emitting elementhaving an OLED, an element with liquid crystal, a memory element, a thinfilm diode, a photoelectric conversion element of silicon PIN junction,and a silicon resistor element.

When light is to pass through the second bonding member, a materialhighly transmissive of light is preferred for the second bonding member.For example, if light emitted from an OLED or light from backlight is topass through the second bonding member, the light transmittance can beimproved by adjusting the thickness of the second bonding member.

It is also possible to give flexibility to the entire device byadjusting the thickness of the second bonding member. Therefore thesecond bonding member can be bonded to various kinds of base members.The base member may have a flat face or a curved face, or may bebendable, or may be film-like. The material of the base member may haveany composition such as plastic, glass, a metal, or ceramics. If thebonding member is pasted on a curved face base member, a curved facedisplay is obtained and used as indicators on dashboard, show windows,and the like.

Although the second bonding member alone is used as a supporter in theabove manufacture process, the first bonding member alone may serve as asupporter. In this case, materials of the first bonding member andsecond bonding member are chosen as needed, for example, a materialinsoluble in a solvent is used for the first bonding member whereas amaterial soluble in this solvent is used for the second bonding member.After the bonding members are bonded, they are immersed in the solventto peel the second substrate and the third substrate off leaving thefirst bonding member to serve as a supporter by itself. When thesupporter is the first bonding member alone, the bonding member is incontact with the uppermost layer of the peeled layer. Although thesecond bonding member alone is used as a supporter in the abovemanufacture process, the first bonding member or the second bondingmember alone may serve as a supporter. In this case, materials of thefirst bonding member and second bonding member are appropriatelyselected. Another structure of the present invention disclosed in thisspecification relates to a method of manufacturing a semiconductordevice, comprising: a first step of forming on a first substrate a layerto be peeled that includes a semiconductor element; a second step ofbonding a second substrate to the layer to be peeled using a firstbonding member to sandwich the layer to be peeled between the firstsubstrate and the second substrate; a third step of separating the firstsubstrate from the layer to be peeled; a fourth step of bonding a thirdsubstrate to the peeled layer using a second bonding member to sandwichthe peeled layer between the second substrate and the third substrate;and a fifth step of separating the third substrate from the peeled layerand separating the second substrate from the peeled layer to form thepeeled layer that uses the first bonding member and the second bondingmember as a supporter.

In the above fifth step, the second substrate and the third substrateare both separated from the peeled layer in the same step. The secondsubstrate and the third substrate may be separated in different stepsand which of them is separated first is not fixed.

In the above process of the present invention, the first bonding memberand the second bonding member may be made of the same material ordifferent materials as long as the materials can be removed by a solventor light. Desirably, the adhesion of the first bonding member to thepeeled layer is stronger than its adhesion to the second substrate andthe adhesion of the second bonding member to the peeled layer isstronger than its adhesion to the third substrate.

For example, if the second bonding member is made of a photosensitiveadhesive, the third substrate can be separated from the second bondingmember by irradiating the second bonding member with light in the fifthstep. If the first bonding member is made of a photosensitive adhesive,the second substrate can be separated from the first bonding member byirradiating the first bonding member with light in the fifth step.Accordingly, both the second substrate and third substrate can beseparated from the peeled layer in the same step if the samephotosensitive adhesive is used for the first bonding member and thesecond bonding member.

When using a photosensitive adhesive, the first substrate is preferablya light-transmissive substrate, for example, a glass substrate or aquartz substrate.

If a photosensitive adhesive is not chosen, the second substrate or thethird substrate can be separated from the peeled layer by lowering theadhesion of the bonding member to the substrate by using a plastic filmwith an AlN_(X)O_(Y) film formed on its surface as the second substrateor the third substrate.

Through the above process of the present invention, a peeled layersandwiched between the first bonding member and the second bondingmember is obtained.

When a plastic film is used as the second substrate and an elementformed on the first substrate is being transferred to the plastic film,in other words, when the layer including the element is bonded to thefilm using a bonding member and the film is lifted, the film could bebent and the layer including the element may be cracked because of thebend. The possibility of crack is lowered by transferring an elementonto a plastic film in the following procedure: an element formed on thesubstrate is pasted on a second substrate that is highly rigid using abonding member before the substrate is peeled off. Following a plasticfilm (third substrate) is pasted on the layer including the elementusing a bonding member, the second substrate is separated from the layerincluding the element.

The other aspect of the present invention disclosed in thisspecification relates to a method of manufacturing a semiconductordevice, comprising: a first step of forming on a first substrate a layerto be peeled that includes a semiconductor element; a second step ofbonding a second substrate to the layer to be peeled using a firstbonding member to sandwich the layer to be peeled between the firstsubstrate and the second substrate; a third step of separating the firstsubstrate from the layer to be peeled; a fourth step of bonding a thirdsubstrate to the peeled layer using a second bonding member to sandwichthe peeled layer between the second substrate and the third substrate;and a fifth step of separating the second substrate from the peeledlayer to form the peeled layer that uses the second bonding member andthe third substrate as a supporter.

In the above structure, the manufacture method is characterized in thatthe material of the first substrate and second substrate has a rigidityhigher than the rigidity of the third substrate. In this specification,rigidity refers to the ability of an object to withstand breakage bybend or twist.

In the above structure, the fifth step is a step of dissolving the firstbonding member in a solvent to remove the first bonding member andseparate the second substrate from the peeled layer, or a step ofseparating the second substrate from the peeled layer by irradiating thefirst bonding member made of a photosensitive adhesive with light.

By keeping the plastic film (the third substrate) bonded without peelingit off as this, a semiconductor device with a supporter composed of thethird substrate and the second bonding member is obtained.

Another structure of the present invention disclosed in thisspecification is a semiconductor device characterized in that a plasticsubstrate and a bonding member make a supporter and an element is formedon an insulating film that is in contact with the bonding member.

In the above structure, the element is a thin film transistor, a lightemitting element having an OLED, an element with liquid crystal, amemory element, a thin film diode, a photoelectric conversion element ofsilicon PIN junction, or a silicon resistor element.

In the above structure, the semiconductor device is characterized inthat the plastic substrate is pasted on a flat face or curved face basemember, and a thin and light-weight semiconductor device can beobtained. Examples of this semiconductor device include video cameras,digital cameras, goggle type displays, indicators for automobiles andmachines (such as a car navigation system and a speed meter), personalcomputers, and portable information terminals.

In the above processes, the third step is for separating the firstsubstrate from the layer to be peeled by a peeling method in which twolayers are peeled by applying a mechanical force and utilizing the filmstress between the two layers. How the first substrate is separated isnot particularly limited, and a method of separating the substrate fromthe peeled layer by providing a separation layer between the peeledlayer and the first substrate and removing the separation layer with achemical (etchant), or a method of separating the first substrate fromthe peeled layer by forming a separation layer from amorphous silicon(or polysilicon) between the peeled layer and the first substrate andirradiating the separation layer with laser light through the firstsubstrate to release hydrogen contained in amorphous silicon and createa gap, or other methods can be employed. If the first substrate ispeeled off using laser light, it is desirable to set the heat treatmenttemperature to 410° C. or lower to form the element included in thepeeled layer, so that hydrogen is not released before peeling.

The peeling method that utilizes film stress between two layers is themost desirable because it does not damage the peeled layer and it canpeel throughout the entire surface without fail irrespective of whetherthe peeled layer has a small area or a large area. Specifically, a firstmaterial layer that is a metal layer or a nitride layer is formed on afirst substrate, a second material layer that is an oxide layer isformed by sputtering, an element is formed on the second material layer,and a mechanical force is applied to separate the first material layerand the second material layer from each other at the interface. Thelaminate of the first material layer and second material layer is freefrom peeling or other process disturbance but can be easily and cleanlyseparated at a point in the second material layer or at the interface bya physical measure, typically application of a mechanical force, forexample, by pulling at it by hands.

In other words, the bond between the first material layer and the secondmaterial layer is strong enough to withstand thermal energy but weakagainst dynamic energy to cause peeling since there is stress distortionbetween the first material layer having tensile stress and the secondmaterial layer having compressive stress immediately before the layersare peeled off. The present inventors have found that the peelingphenomenon is deeply related with the film internal stress and call apeeling process that utilizes the film internal stress as a stress peeloff process.

When the above peeling method using the first material layer and thesecond material layer is employed in the semiconductor devicecharacterized by using the plastic substrate and the bonding member as asupporter and forming an element on an insulating film that is incontact with the bonding member, the insulating film that is in contactwith the bonding member serves as the second material layer. Theinsulating film is preferably an oxide film which is formed bysputtering and serves as an oxide layer which contains a noble gaselement. The noble gas element is one or more kinds of elements selectedfrom the group consisting of He, Ne, Ar, Kr, and Xe. With a noble gaselement contained, the second material layer can make the semiconductordevice flexible.

Furthermore, the term plastic substrate as used herein is notparticularly limited as long as it is a plastic substrate havingplasticity; for example, it refers to a substrate consisting ofpolyethylene terephthalate (PET), polyethersulfone (PES), polyethylenenaphthalate (PEN), polycarbonate (PC), nylon, polyetheretherketone(PEEK), polysulfone (PSF), polyetherimide (PEI), polyarylate (PAR),polybutylene terephthalate (PBT), or polyimide.

An experiment has been conducted to examine the adhesion for each of asilicon nitride film, an AlN film, and an AlNO film when formed betweena plastic substrate (PC film) and a bonding member. The silicon nitridefilm is separated from the plastic substrate while it keeps adhered tothe bonding member. On the other hand, the AlN film and the AlNO filmare separated only from the bonding member while they keep adhered tothe plastic substrate.

As shown in FIGS. 16A to 16G, another aspect of the present inventionrelates to a method of manufacturing a semiconductor device, comprising:a first step of forming on a first substrate 10 a layer to be peeled 13that includes a semiconductor element; a second step of bonding a secondsubstrate 15 to the layer to be peeled 13 using a first bonding member14 to sandwich the layer to be peeled between the first substrate andthe second substrate; a third step of separating the first substrate 10from the layer to be peeled 13; a fourth step of bonding a thirdsubstrate 17 in which a protective film 18 is formed to the peeled layerusing a second bonding member 16 to sandwich the peeled layer betweenthe second substrate and the third substrate; and a fifth step ofseparating the second substrate from the peeled layer and separating thethird substrate from the second bonding member to form the peeled layerthat uses the second bonding member 16 and the protective film 18 as asupporter.

In the above structure, the manufacture method is characterized in thatthe protective film is a silicon nitride film or a silicon oxynitridefilm. By forming the protective film, moisture and impurities from theoutside can be effectively blocked to avoid contamination.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIGS. 1A to 1G are process diagrams showing Embodiment Mode 1;

FIGS. 2A to 2G are process diagrams showing Embodiment Mode 2;

FIGS. 3A to 3G are process diagrams showing Embodiment Mode 3;

FIG. 4 is a sectional view of a first substrate having elements;

FIG. 5 is a sectional view of a light emitting device having an OLED;

FIGS. 6A and 6B are a top view of a light emitting device having an OLEDand a sectional view thereof, respectively;

FIG. 7 is a sectional view of a light emitting device having an OLED;

FIG. 8 is a sectional view of an active matrix liquid crystal displaydevice;

FIG. 9 is a graph showing the V-I characteristic of an n-channel TFTbefore peeling;

FIG. 10 is a graph showing the V-I characteristic of a p-channel TFTbefore peeling;

FIG. 11 is a graph showing the V-I characteristic of an n-channel TFTafter peeling;

FIG. 12 is a graph showing the V-I characteristic of a p-channel TFTafter peeling;

FIGS. 13A to 13F are diagrams showing examples of electronic equipment;

FIG. 14 is a diagram showing examples of electronic equipment;

FIGS. 15A to 15C are diagrams showing examples of electronic equipment;

FIGS. 16A to 16G are a process diagram example showing the presentinvention.

FIG. 17 is a photographic diagram showing an external view of a panel;and

FIG. 18 is a photographic diagram showing the panel emitting a light.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiment Modes of the present invention will be described below.

Embodiment Mode 1

The following is a brief description on a typical peeling procedure andsemiconductor device manufacturing method using the present invention.The description will be given with reference to FIGS. 1A to 1G.

In FIG. 1A, reference numeral 10 denotes a first substrate, 11, a firstmaterial layer that is a nitride layer or a metal layer, 12, a secondmaterial layer that is an oxide layer, and 13, a layer to be peeled.

The first substrate 10 in FIG. 1A can be a glass substrate, a quartzsubstrate, a ceramic substrate, or the like. A semiconductor substrate,typically a silicon substrate, or a metal substrate, typically astainless steel substrate, may also be used.

First, the first material layer 11 is formed on the substrate 10 asshown in FIG. 1A. The first material layer 11 may have compressivestress or tensile stress immediately after it is formed. However, it isimportant to use for the first material layer 11 a material which isfree from peeling or other disturbances caused by heat treatment, orlaser light irradiation, for forming the layer to be peeled and whichgives a tensile stress of 1 to 1×10¹⁰ dyne/cm² after the layer to bepeeled is formed. A typical example thereof is a single layer of anelement selected from the group consisting of W, WN, TiN, and TiW, or ofan alloy material or compound material mainly containing the aboveelements, or a laminate of the above elements. The first material layer11 is formed by sputtering.

Next, the second material layer 12 is formed on the first material layer11. It is important to use for the second material layer 12 a materialwhich is free from peeling or other disturbances caused by heattreatment, or laser light irradiation, for forming the layer to bepeeled and which gives a tensile stress of 1 to 1×10¹⁰ dyne/cm² afterthe layer to be peeled is formed. A typical example of the secondmaterial layer 12 is a single layer or a laminate of silicon oxide,silicon oxynitride, and a metal oxide. The second material layer 12 maybe formed by sputtering. When forming the second material layer 12 bysputtering, noble gas, typically argon gas, is introduced into thechamber so that a minute amount of noble gas element is contained in thesecond material layer 12.

The first material layer 11 and the second material layer 12 are eachset to have an appropriate thickness in a range between 1 mm and 100 nmto adjust the internal stress of the first material layer 11 and theinternal stress of the second material layer 12.

FIGS. 1A to 1G show an example in which the first material layer 11 isformed in contact with the substrate 10 in order to simplify theprocess. However, an insulating layer or metal layer that serves as abuffer layer may be formed between the substrate 10 and the firstmaterial layer 11 to improve the adhesion of 11 to the substrate 10.

Next, the layer to be peeled 13 is formed on the second material layer12 (FIG. 1A). The layer to be peeled 13 is a layer that includes variouselements (a thin film transistor, a light emitting element having anOLED, an element with liquid crystal, a memory element, a thin filmdiode, a photoelectric conversion element of silicon PIN junction, asilicon resistor element). When the element is one with liquid crystal,the layer to be peeled 13 includes an opposite substrate. The layer tobe peeled 13 can be formed by heat treatment at a temperature the firstsubstrate 10 can withstand. In the present invention, a film is notpeeled off by the heat treatment for forming the layer to be peeled 13even though the internal stress of the second material layer 12 isdifferent from the internal stress of the first material layer 11.

The next processing is for partially lowering the adhesion between thefirst material layer 11 and the second material layer 12. The processingfor partially lowering the adhesion is laser irradiation in which thesecond material layer or the first material layer is partiallyirradiated with light along the perimeter of the region to be peeledoff, or local pressurizing externally applied along the perimeter of theregion to be peeled off to damage a part on the inside of the secondmaterial layer or a part of the interface. Specifically, a diamond penor the like is used to depress a hard needle vertically and apply loadwhile the layers are moved. Preferably, scriber apparatus is used andthe depression amount is set to 0.1 to 2 mm to apply a pressure whilemoving the layers. To provide a portion that facilitates the peelingphenomenon, namely an initiator, in this way prior to peeling isimportant. Owing to the preprocessing for selectively (partially)lowering the adhesion, peeling failure is avoided and the yield isimproved.

Next, a second substrate 15 is bonded to the layer to be peeled 13 usinga first bonding member 14 (FIG. 1B). Reaction-cured adhesives,thermally-curable adhesives, photo-curable adhesives such as UV-curableadhesives, anaerobic adhesives, and other various kinds of curableadhesives can be used for the first bonding member 14. These adhesivesmay be soluble in solvents or may be photosensitive and be reduced inadhesion when irradiated with light. These adhesives can have anycomposition and may be, for example, epoxy-based, acrylate-based, orsilicone-based. The adhesives are formed into a bonding member byapplication, for example. The first bonding member is removed in a laterstep. Here, an adhesive material soluble in a solvent is chosen for thefirst bonding member.

The second substrate 15 can be a glass substrate, a quartz substrate, aceramic substrate, a plastic substrate or the like. A semiconductorsubstrate, typically a silicon substrate, or a metal substrate,typically a stainless steel substrate, may also be used. Incidentally,in the case where a photosensitive bonding member is used for the firstbonding member or the second bonding member, as one of the firstsubstrate and the second substrate, there is preferably used a substratehaving light transmittance.

Next, the first substrate 10 on which the first material layer 11 isformed is pulled off by a physical measure in the direction indicated bythe arrow in FIG. 1C starting from the side of the region where theadhesion is partially lowered (FIG. 1C). Since the second material layer12 has compressive stress and the first material layer 11 has tensilestress, the first substrate can be pulled off with a relatively smallforce (for example, by hands, pressure of gas sprayed through a nozzle,supersonic, or the like).

In this way the layer to be peeled 13 formed on the second materiallayer 12 can be separated from the first substrate 10. The state afterpeeling is shown in FIG. 1D.

Subsequently, a third substrate 17 is bonded to the second materiallayer 12 (and the peeled layer 13) using a second bonding member 16formed of a different material than the material of the first bondingmember 14 (FIG. 1E). It is important that the adhesion of the secondbonding member 16 to the second material layer 12 (and the peeled layer13) is stronger than its adhesion to the third substrate 17.

Reaction-cured adhesives, thermally-curable adhesives, photo-curableadhesives such as UV-curable adhesives, anaerobic adhesives, and othervarious kinds of curable adhesives can be used for the second bondingmember 16. These adhesives may be soluble in solvents or may bephotosensitive and reduced in adhesion when irradiated with light. Theseadhesives can have any composition and may be epoxy-based,acrylate-based, or silicone-based. The adhesives are formed into abonding member by application, for example. The second bonding memberbecomes a supporter of peeled layer in a later step. Here, UV-curableadhesives are used for the second bonding member 16.

The third substrate 17 can be a glass substrate, a quartz substrate, aceramic substrate, a plastic substrate, or the like. A semiconductorsubstrate, typically a silicon substrate, or a metal substrate,typically a stainless steel substrate, may also be used. Here, in orderto lower the adhesion of the second bonding member to the thirdsubstrate, a plastic film with an AlN_(X)O_(Y) film formed on itssurface is used as the third substrate 17.

The AlN_(X)O_(Y) film on the plastic film is formed by sputtering using,for example, an aluminum nitride (AlN) target in an atmosphere obtainedby mixing argon gas, nitrogen gas, and oxygen gas. It is sufficient ifthe AlN_(X)O_(Y) film contains a few or more atm % of nitrogen,preferably, 2.5 to 47.5 atm %. The nitrogen concentration can beadjusted by adjusting sputtering conditions (the substrate temperature,the type and flow rate of material gas, the film formation pressure, andthe like) as needed.

Next, the layers are immersed in a solvent to separate the secondsubstrate 15 and the third substrate 17 (FIG. 1F). The first bondingmember is easily removed since it is made of an adhesive materialsoluble in a solvent, thereby separating the second substrate 15 fromthe peeled layer 13. On the other hand, the solvent permeates theinterface between the third substrate 17 and the second bonding member16 and weakens the adhesion at the interface, to thereby separate thethird substrate 17 from the second material layer 12. Although thesecond substrate 15 and the third substrate 17 are separated in the samestep in the example shown here, there is no particular limitation. Thesubstrates may be separated in different steps and which of them isseparated first is not fixed.

The element included in the peeled layer 13 is formed such that itsinput/output terminal is exposed in the uppermost layer of the peeledlayer (namely, the layer closest to the second substrate side).Accordingly, it is desirable to remove the first bonding member on thepeeled layer surface completely after the step of separating the secondsubstrate, so that the input/output terminal portion is exposed.

Through the above steps, a semiconductor device having the peeled layer13 with the second bonding member 16 serving as a supporter ismanufactured. (FIG. 1 g) The thus obtained semiconductor device is thin,light-weight, and flexible since the supporter consists solely of thesecond bonding member 16.

In the example shown here, the semiconductor device is completed throughthe above steps. The above steps may be used to finish the semiconductordevice halfway. For instance, element forming steps may be added to theabove steps so that a peeled layer including a circuit that is composedof TFTs is formed following the above steps and then the thus obtainedpeeled layer that uses a second bonding member as a supporter can beused in the element forming steps to complete various kinds ofsemiconductor devices, typically a light emitting device having an OLEDor a liquid crystal display device.

For example, an active matrix light emitting device can be manufacturedby arranging pixel electrodes to form a matrix pattern, forming a secondbonding member that has TFTs connected to the pixel electrodes throughthe above steps, and then forming OLEDs that use the pixel electrodes ascathodes or anodes. The thus obtained light emitting device is thin andlight-weight since the supporter consists solely of the second bondingmember.

It is also possible to manufacture a passive light emitting devicehaving an OLED.

Also, an active matrix liquid crystal display device can be manufacturedby arranging pixel electrodes to form a matrix pattern and forming asecond bonding member that has TFTs connected to the pixel electrodesthrough the above steps, followed by an opposite substrate pasting stepand a liquid crystal injection step. Specifically, a seal member or thelike is used to paste an opposite substrate to a bonding member providedwith TFTs that are connected to pixel electrodes while keeping a certaindistance between the opposite substrate and the bonding member with agap holding member such as a spacer. Then a liquid crystal material isheld between the opposite substrate and the pixel electrodes to completethe liquid crystal display device. The thus obtained liquid crystaldisplay device is thin and light-weight since the supporter is composedof the second bonding member and the opposite substrate alone.

Embodiment Mode 2

Embodiment Mode 1 shows an example in which the second bonding memberalone serves as a supporter. In this embodiment mode, an example ofusing the first bonding member and the second bonding member as asupporter is shown. FIG. 2A to FIG. 2E are roughly identical with FIGS.1A to 1E. Therefore, detailed descriptions will be omitted here and onlydifferences between Embodiment Mode 1 and Embodiment Mode 2 will bedescribed.

In FIGS. 2A to 2G, reference numeral 20 denotes a first substrate, 21, afirst material layer that is a nitride layer or a metal layer, 22, asecond material layer that is an oxide layer, 23, a layer to be peeled,24, a first bonding member, 25, a second substrate, 26, a second bondingmember, and 27, a third substrate.

First, according to Embodiment Mode 1, there is obtained a state of FIG.2E in the same procedure.

Here, reaction-cured adhesives, thermally-curable adhesives,photo-curable adhesives such as UV-curable adhesives, anaerobicadhesives, and other various kinds of curable adhesives can be used forthe first bonding member 24. These adhesives may be soluble in solventsor may be photosensitive and reduced in adhesion when irradiated withlight. These adhesives can have any composition and may be epoxy-based,acrylate-based, or silicone-based. The adhesives are formed into abonding member by application, for example. The first bonding memberbecomes a supporter in a later step. Here, thermally-curable adhesiveswhich are reduced in adhesion when irradiated with ultraviolet rays areused for the first bonding member. It is important that the adhesion ofthe first bonding member 24 to the peeled layer 23 is stronger than itsadhesion to the second substrate 25.

In order to lower the adhesion of the first bonding member to the secondsubstrate, a plastic film with an AlN_(X)O_(Y) film formed on itssurface may be used as the second substrate.

The material of the second bonding member 26 may be the same as thematerial of the first bonding member 24. Here, a thermally-curableadhesive the adhesion of which is lowered when irradiated withultraviolet rays is used for the second bonding member. The secondbonding member too serves as a supporter of the peeled layer in a laterstep. It is important that the adhesion of the second bonding member 26to the second material layer 22 (and the peeled layer 23) is strongerthan its adhesion to the third substrate 27.

In order to lower the adhesion of the second bonding member to the thirdsubstrate, a plastic film with an AlN_(X)O_(Y) film formed on itssurface may be used as the third substrate.

The state of FIG. 2E is obtained by following the procedure ofEmbodiment Mode 1. Then the bonding members are irradiated withultraviolet rays to lower the adhesion of the first bonding member 24 tothe second substrate 25 and the adhesion of the second bonding member 26to the third substrate 27, thereby separating the second substrate andthe third substrate (FIG. 2F). Although the second substrate 25 and thethird substrate 27 are separated in the same step in the example shownhere, there is no particular limitation. The substrates may be separatedin different steps and which of them is separated first is not fixed.Also, this embodiment mode may be combined with Embodiment Mode 1.

Although a thermally-curable adhesive that is lowered in adhesion byultraviolet irradiation is used in the example shown here, otheradhesive materials may be used. For example, a UV-curable adhesive maybe used for the first bonding member and the second bonding member. Inthis case, a plastic film with an AlN_(X)O_(Y) film formed on itssurface is used as the second substrate and bonded by the first bondingmember made of a UV-curable adhesive, a plastic film with anAlN_(X)O_(Y) film formed on its surface is used as the third substrateand bonded by the second bonding member made of a UV-curable adhesive.Then, the layers are immersed in a solvent and the solvent permeates theinterface between the third substrate and the second bonding member toweaken the adhesion at the interface, thereby separating the thirdsubstrate from the second material layer. Similarly, the secondsubstrate is separated from the first bonding member.

The element included in the peeled layer 23 is formed such that itsinput/output terminal is exposed in the uppermost layer of the peeledlayer (namely, the layer closest to the second substrate side).Accordingly, it is desirable to selectively remove the first bondingmember that covers the input/output terminal portion after the step ofseparating the second substrate, so that the input/output terminalportion is exposed.

Through the above steps show in FIG. 2G, a semiconductor device havingthe peeled layer 23 with the first bonding member 24 and the secondbonding member 26 serving as a supporter is manufactured. Note that thepeeled layer 23 is sandwiched between the first bonding member 24 andthe second bonding member 26. The thus obtained semiconductor device isthin, light-weight, and flexible since the supporter consists solely ofthe first bonding member 24 and the second bonding member 26.

In the example shown here, the semiconductor device is completed throughthe above steps. The above steps may be used to finish the semiconductordevice halfway. For instance, element forming steps may be added to theabove steps so that a peeled layer including a circuit that is composedof TFTs is formed following the above steps and then the thus obtainedpeeled layer that uses a first bonding member and a second bondingmember as a supporters can be used in the element forming steps tocomplete various kinds of semiconductor devices, typically a lightemitting device having an OLED or a liquid crystal display device.

This embodiment mode may be combined freely with Embodiment Mode 1.

Embodiment Mode 3

Embodiment Mode 1 shows an example in which the second bonding memberalone serves as a supporter. In this embodiment mode, art example ofusing the second bonding member and the third substrate as a supporteris shown.

FIGS. 3A to 3E are roughly identical with FIGS. 1A to 1E. Thereforedetailed descriptions will be omitted here and only differences betweenEmbodiment Mode 1 and Embodiment Mode 2 will be described.

In FIGS. 3A to 3G, reference numeral 30 denotes a first substrate, 31, afirst material layer that is a nitride layer or a metal layer, 32, asecond material layer that is an oxide layer, 33, a layer to be peeled,34, a first bonding member, 35, a second substrate, 36, a second bondingmember, and 37, a third substrate.

First, according to Embodiment Mode 1, there is obtained a state of FIG.3E in the same procedure.

The first substrate 30 can be a glass substrate, a quartz substrate, aceramic substrate, or the like. A semiconductor substrate, typically asilicon substrate, or a metal substrate, typically a stainless steelsubstrate, may also be used. Here, there is used a glass substrate(#1737) having a thickness of 0.7 mm.

Here, a quartz substrate (1.1 mm in thickness) thicker and higher inrigidity than the first substrate 30 is used as the second substrate 35.If a plastic film is used as the second substrate, when an elementformed on the first substrate 30 is being transferred to the plasticfilm, in other words, when the peeled layer 33 is bonded to the filmusing the first bonding member 34 and the film is lifted, there was afear that the film could be bent and the peeled layer 33 may be crackedbecause of the bend. Therefore, the possibility of crack is lowered bythe following procedure: the peeled layer 33 formed on the firstsubstrate 30 is pasted on the second substrate 35 that is highly rigidusing the first bonding member 34, the first substrate 30 is peeled off,a plastic film (third substrate 37) is pasted on the layer including theelement using the second bonding member 36, and then separating thesecond substrate 35.

The third substrate 37 here is a plastic film.

Here, an adhesive material soluble in a solvent is chosen for the firstbonding member 34.

The material used here for the second bonding member 36 is high inadhesion both to the third substrate and to the peeled layer.

The state of FIG. 3E is obtained following the procedure of EmbodimentMode 1. Then, the layers are immersed in a solvent to separate thesecond substrate 35 alone (FIG. 3F). Formed from an adhesive materialsoluble in a solvent, the first bonding member is easily removed toseparate the second substrate 35 from the peeled layer 33.

The element included in the peeled layer 33 is formed such that itsinput/output terminal is exposed in the uppermost layer of the peeledlayer (namely, the layer closest to the second substrate side).Accordingly, it is desirable to remove the first bonding member on thepeeled layer surface completely after the step of separating the secondsubstrate, so that the input/output terminal portion is exposed.

In the example shown here, the first bonding member 34 is made of anadhesive soluble in a solvent and is immersed in a solvent to separatethe second substrate. However, there is no particular limitation and,for example, the second substrate maybe separated by irradiating withultraviolet rays the first bonding member that is made of thethermally-curable adhesive (whose adhesion is lowered by ultravioletirradiation) shown in Embodiment Mode 2.

Through the above steps, a semiconductor device having the peeled layer33 with the second bonding member 36 and the third substrate 37 servingas a supporter is manufactured as shown in FIG. 3G. The oxide layer 32that is the second material layer is interposed between the secondbonding member 36 and the peeled layer 33. The thus obtainedsemiconductor device is flexible throughout since the second materiallayer 32 is formed by sputtering and a minute amount of noble gaselement is contained in the second material layer 32.

In the example shown here, the semiconductor device is completed throughthe above steps. The above steps may be used to finish the semiconductordevice halfway. For instance, element forming steps may be added to theabove steps so that a peeled layer including a circuit that is composedof TFTs is formed following the above steps and then the thus obtainedpeeled layer that uses a second bonding member and third substrate as asupporter can be used in the element forming steps to complete variouskinds of semiconductor devices, typically a light emitting device havingan OLED or a liquid crystal display device.

This embodiment mode may be combined freely with Embodiment Mode 1 orEmbodiment Mode 2.

More detailed descriptions will be given on the present inventionstructured as above through the following embodiments.

Embodiment 1

Here, a detailed description will be given on a method of manufacturinga light emitting device having an OLED in which a pixel portion(n-channel TFTs and p-channel TFTs) and TFTs (n-channel TFTs andp-channel TFTs) of a driving circuit that are provided in the peripheryof the pixel portion are formed on the same substrate at the same time(FIG. 4).

First, a silicon oxynitride film (not shown) is formed by plasma CVD tohave a thickness of 100 nm on a heat-resistant glass substrate (firstsubstrate 101) with a thickness of 0.7 mm. The silicon oxynitride filmis for protecting the substrate from later dry etching and forpreventing contamination of an etching chamber, and is not particularlynecessary.

Although a glass substrate is used as the first substrate 101 in thisembodiment, there is no particular limitation and it may be a quartzsubstrate, a semiconductor substrate, a ceramic substrate, or a metalsubstrate.

Next, a tungsten film is formed as a first material layer 102 on thesilicon oxynitride film by sputtering to have a thickness of 50 nm. Thetungsten film formed by sputtering is fluctuated in thickness about theperimeter of the substrate. Accordingly, the tungsten film is patternedby forming a resist for dry etching of the perimeter of the substratealone. Although patterning is conducted here, it is not particularlynecessary. The first material layer 102 is not limited to the tungstenfilm and other materials, tungsten nitride or titanium nitride, forexample, may be used. The thickness of the first material layer 102 canbe set as needed within a range of 10 to 200 nm.

On the tungsten film, a silicon oxide film is formed as a secondmaterial layer 103 by sputtering to have a thickness of 200 nm. Asilicon oxide film formed by sputtering is used here but othermaterials, an oxide, for example, may be used instead. The thickness ofthe second material layer 103 can be set as needed within a range of 50to 400 nm. The first material layer 102 (tungsten film) and the secondmaterial layer 103 (silicon oxide film) are formed on the firstsubstrate as this, an element is formed on the second material layer ina later step, and then a mechanical force is applied to separate thefirst material layer and the second material layer from each other atthe interface. It is preferable to create a flow of noble gas such asargon by sputtering during forming the second material layer 103 so thata minute amount of noble gas element is contained in the second materiallayer 103.

Next, a silicon oxynitride film is formed as a lower layer of a baseinsulating film on the silicon oxide film by plasma CVD at a temperatureof 400° C. using SiH₄, NH₃, and N₂O as material gas (the compositionratio of the silicon oxynitride film: Si=32%, O=27%, N=24%, H=17%). Thesilicon oxynitride film has a thickness of 50 nm (preferably 10 to 200nm). The surface of the film is washed with ozone water and then anoxide film on the surface is removed by diluted fluoric acid (diluteddown to 1/100). Next, a silicon oxynitride film is formed as an upperlayer of the base insulating film by plasma CVD at a temperature of 400°C. using SiH₄ and N₂O as material gas (the composition ratio of thesilicon oxynitride film: Si=32%, O=59%, N=7%, H=2%). The siliconoxynitride film has a thickness of 100 nm (preferably 50 to 200 nm) andis laid on the lower layer to form a laminate. Without exposing thelaminate to the air, a semiconductor film having an amorphous structure(here, an amorphous silicon film) is formed on the laminate by plasmaCVD at a temperature of 300° C. using SiH₄ as material gas. Thesemiconductor film is 54 nm (preferably 25 to 80 nm) in thickness.

A base insulating film 104 in this embodiment has a two-layer structure.However, the base insulating film may be a single layer or more than twolayers of insulating films mainly containing silicon. The material ofthe semiconductor film is not limited but it is preferable to form thesemiconductor film from silicon or a silicon germanium alloy(Si_(X)Ge_(1-x) (X=0.0001 to 0.02)) by a known method (sputtering,LPCVD, plasma CVD, or the like). Plasma CVD apparatus used may be onethat processes wafer by wafer or one that processes in batch. The baseinsulating film and the semiconductor film may be formed in successionin the same chamber to avoid contact with the air.

The surface of the semiconductor film having an amorphous structure iswashed and then a very thin oxide film, about 2 nm in thickness, isformed on the surface using ozone water. Next, the semiconductor film isdoped with a minute amount of impurity element (boron or phosphorus) inorder to control the threshold of the TFTs. Here, the amorphous siliconfilm is doped with boron by ion doping in which diborane (B₂H₆) isexcited by plasma without mass separation. The doping conditions includesetting the acceleration voltage to 15 kV, the flow rate of gas obtainedby diluting diborane to 1% with hydrogen to 30 sccm, and the dose to2×10¹²/cm².

Next, a nickel acetate solution containing 10 ppm of nickel by weight isapplied by a spinner. Instead of application, nickel may be sprayed ontothe entire surface by sputtering.

The semiconductor film is subjected to heat treatment to crystallize itand obtain a semiconductor film having a crystal structure. The heattreatment is achieved in an electric furnace or by irradiation ofintense light. When heat treatment in an electric furnace is employed,the temperature is set to 500 to 650° C. and the treatment lasts for 4to 24 hours. Here, a silicon film having a crystal structure is obtainedby heat treatment for crystallization (at 550° C. for 4 hours) afterheat treatment for dehydrogenation (at 500° C. for an hour). Althoughthe semiconductor film is crystallized here by heat treatment using anelectric furnace, it may be crystallized by a lamp annealing apparatuscapable of achieving crystallization in a short time. This embodimentemploys a crystallization technique in which nickel is used as a metalelement for accelerating crystallization of silicon. However, otherknown crystallization techniques, solid phase growth and lasercrystallization, for example, may be employed.

An oxide film on the surface of the silicon film having a crystalstructure is removed by diluted fluoric acid or the like. Then in orderto enhance the crystallization rate and repair defects remaining incrystal grains, the silicon film is irradiated with laser light (XeCl,the wavelength: 308 nm) in the air or in an oxygen atmosphere. The laserlight may be excimer laser light having a wavelength of 400 nm or less,or the second harmonic or third harmonic of a YAG laser. Pulse laserlight having a repetition frequency of 10 to 1000 Hz is employed. Thelaser light is collected by an optical system to have an energy densityof 100 to 500 mJ/cm² and scans the silicon film surface at anoverlapping ratio of 90 to 95%. Here, the film is irradiated with laserlight at a repetition frequency of 30 Hz and an energy density of 470mJ/cm² in the air. Since the laser light irradiation is conducted in theair or in an oxygen atmosphere, an oxide film is formed on the surfaceas a result. A pulse laser is used in the example shown here but acontinuous wave laser may be employed instead. It is preferable toemploy a continuous wave solid-state laser and the second to fourthharmonic of the fundamental wave in order to obtain crystals of largegrain size when crystallizing an amorphous semiconductor film.Typically, the second harmonic (532 nm) or third harmonic (355 nm) of aNd:YVO₄ laser (fundamental wave: 1064 nm) is employed. When using acontinuous wave laser, laser light emitted from a 10 W power continuouswave YVO₄ laser is converted into harmonic by a non-linear opticalelement. Alternatively, the harmonic is obtained by putting a YVO₄crystal and a non-linear optical element in a resonator. The harmonic ispreferably shaped into oblong or elliptical laser light on anirradiation surface by an optical system and then irradiates anirradiation object. The energy density required at this point is about0.01 to 100 MW/cm² (preferably 0.1 to 10 MW/cm²). During theirradiation, the semiconductor film is moved relative to the laser lightat a rate of 10 to 2000 cm/s.

The oxide film formed by laser light irradiation is removed by dilutedfluoric acid and then the surface is treated with ozone water for 120seconds to form as a barrier layer an oxide film having a thickness of 1to 5 nm in total. The barrier layer here is formed using ozone water butit may be formed by oxidizing the surface of the semiconductor filmhaving a crystal structure through ultraviolet irradiation in an oxygenatmosphere, or formed by oxidizing the surface of the semiconductor filmhaving a crystal structure through oxygen plasma treatment, or by usingplasma CVD, sputtering or evaporation to form an about 1 to 10 nm thickoxide film. In this specification, a barrier layer refers to a layerwhich has a quality and thickness that allows a metal element to pass ina gettering step and which serves as an etching stopper in a step ofremoving the layer serving as a gettering site.

Next, an amorphous silicon film containing argon is formed on thebarrier layer by sputtering to serve as a gettering site. The thicknessof the amorphous silicon film is 50 to 400 nm, here 150 nm. Theconditions for forming the amorphous silicon film here include settingthe film formation pressure to 0.3 Pa, the gas (Ar) flow rate to 50sccm, the film formation power to 3 kW, and the substrate temperature to150° C. The atomic concentration of argon contained in the amorphoussilicon film formed under the above conditions is 3×10²⁰ to 6×10²⁰/cm³and the atomic concentration of oxygen thereof is 1×10¹⁹ to 3×10¹⁹/cm³.Thereafter, heat treatment is conducted in an electric furnace at 550°C. for 4 hours for gettering to reduce the nickel concentration in thesemiconductor film having a crystal structure. Lamp annealing apparatusmay be used instead of an electric furnace.

Using the barrier layer as an etching stopper, the gettering site,namely, the amorphous silicon film containing argon, is selectivelyremoved. Then, the barrier layer is selectively removed by dilutedfluoric acid. Nickel tends to move toward a region having high oxygenconcentration during gettering, and therefore it is desirable to removethe barrier layer that is an oxide film after gettering.

Next, a thin oxide film is formed on the surface of the obtained siliconfilm containing a crystal structure (also called a polysilicon film)using ozone water. A resist mask is then formed and the silicon film isetched to form island-like semiconductor layers separated from oneanother and having desired shapes. After the semiconductor layers areformed the resist mask is removed.

The oxide film is removed by an etchant containing fluoric acid, and atthe same time, the surface of the silicon film is washed. Then, aninsulating film mainly containing silicon is formed to serve as a gateinsulating film 105. The gate insulating film here is a siliconoxynitride film (composition ratio: Si=32%, O=59%, N=7%, H=2%) formed byplasma CVD to have a thickness of 115 nm.

Next, a laminate of a first conductive film with a thickness of 20 to100 nm and a second conductive film with a thickness of 100 to 400 nm isformed on the gate insulating film. In this embodiment, a tantalumnitride film with a thickness of 50 nm is formed on the gate insulatingfilm 105 and then a tungsten film with a thickness of 370 nm is laidthereon. The conductive films are patterned by the procedure shown belowto form gate electrodes and wires.

The conductive materials of the first conductive film and secondconductive film are elements selected from the group consisting of Ta,W, Ti, Mo, Al, and Cu, or alloys or compounds mainly containing theabove elements. The first conductive film and the second conductive filmmay be semiconductor films, typically polycrystalline silicon films,doped with phosphorus or other impurity elements or may be Ag—Pd—Cualloy films. The present invention is not limited to a two-layerstructure conductive film. For example, a three-layer structureconsisting of a 50 nm thick tungsten film, 500 nm thick aluminum-siliconalloy (Al—Si) film, and 30 nm thick titanium nitride film layered inthis order may be employed. When the three-layer structure is employed,tungsten of the first conductive film may be replaced by tungstennitride, the aluminum-silicon alloy (Al—Si) film of the secondconductive film may be replaced by an aluminum-titanium alloy (Al—Ti)film, and the titanium nitride film of the third conductive film may bereplaced by a titanium film. Alternatively, a single-layer conductivefilm may be used.

ICP (inductively coupled plasma) etching is preferred for etching of thefirst conductive film and second conductive film (first etchingtreatment and second etching treatment). By using ICP etching andadjusting etching conditions (the amount of electric power applied to acoiled electrode, the amount of electric power applied to a substrateside electrode, the temperature of the substrate side electrode, and thelike), the films can be etched and tapered as desired. The first etchingtreatment is conducted after a resist mask is formed. The first etchingconditions include applying an RF (13.56 MHz) power of 700 W to a coiledelectrode at a pressure of 1 Pa, employing CF₄, Cl₂, and O₂ as etchinggas, and setting the gas flow rate ratio thereof to 25:25:10 (sccm). Thesubstrate side (sample stage) also receives an RF power of 150 W (13.56MHz) to apply a substantially negative self-bias voltage. The area(size) of the substrate side electrode is 12.5 cm×12.5 cm and the coiledelectrode is a disc 25 cm in diameter (here, a quartz disc on which thecoil is provided). The W film is etched under these first etchingconditions to taper it around the edges. Thereafter, the first etchingconditions are switched to the second etching conditions withoutremoving the resist mask. The second etching conditions include usingCF₄ and Cl₂ as etching gas, setting the gas flow rate ratio thereof to30:30 (sccm), and giving an RF (13.56 MHz) power of 500 W to a coiledelectrode at a pressure of 1 Pa to generate plasma for etching for about30 seconds. The substrate side (sample stage) also receives an RF powerof 20 W (13.56 MHz) to apply a substantially negative self-bias voltage.Under the second etching conditions where a mixture of CF₄ and Cl₂ isused, the W film and the TaN film are etched to almost the same degree.The first etching conditions and the second etching conditionsconstitute the first etching treatment.

Next, the first doping treatment is conducted without removing theresist mask. The first doping treatment employs ion doping or ionimplantation. Typically, phosphorus (P) or arsenic (As) is used as animpurity element that imparts the n type conductivity. Here, ion dopingis used, the flow rate of gas obtained by diluting phosphine (PH₃) withhydrogen to 5% is set to 40 sccm, the dose is set to 2×10¹⁵ atoms/cm²,and the acceleration voltage is set to 80 keV. In this case, the firstconductive layer serves as a mask against the impurity element thatimparts the n type conductivity and a first impurity region is formed ina self-aligning manner. The first impurity region is doped with theimpurity element that imparts the n type conductivity in a concentrationof 1×10²⁰ to 1×10²¹/cm³. Here, a region having the same concentrationrange as the first impurity region is called an n⁺ region.

Next follows the second etching treatment with the resist mask kept inplace. The third etching conditions include using CF₄ and Cl₂ as etchinggas, setting the gas flow rate ratio thereof to 30:30 (sccm), and givingan RF (13.56 MHz) power of 500 W to a coiled electrode at a pressure of1 Pa to generate plasma for etching for 60 seconds. The substrate side(sample stage) also receives an RF power of 20 W (13.56 MHz) to apply asubstantially negative self-bias voltage. Then, the third etchingconditions are switched to the fourth etching conditions withoutremoving the resist mask. The fourth etching conditions include usingCF₄, Cl₂, and O₂ as etching gas, setting the gas flow rate ratio thereofto 20:20:20 (sccm), and giving an RF (13.56 MHz) power of 500 W to acoiled electrode at a pressure of 1 Pa to generate plasma for etchingfor about 20 seconds. The substrate side (sample stage) also receives anRF power of 20 W (13.56 MHz) to apply a substantially negative self-biasvoltage. The third etching conditions and the fourth etching conditionsconstitute the second etching treatment. At this stage, gate electrodes106 to 109 and wires having the first conductive layer as the lowerlayer and the second conductive layer as the upper layer are formed.

Next, the resist mask is removed for the second doping treatment. Thesecond doping treatment employs ion doping or ion implantation. Here,ion doping is used, the flow rate of gas obtained by diluting phosphine(PH₃) with hydrogen to 5% is set to 30 sccm, the dose is set to 1.5×10¹⁴atoms/cm², and the acceleration voltage is set to 90 keV. In this case,the first conductive layer and the second conductive layer serve asmasks against the impurity element that imparts the n type conductivityand a second impurity region is formed in a self-aligning manner. Thesecond impurity region is doped with the impurity element that impartsthe n type conductivity in a concentration of 1×10¹⁶ to 1×10¹⁷/cm³.Here, a region having the same concentration range as the secondimpurity region is called an n⁻ region.

In this embodiment, the first etching treatment comes first and then thefirst doping treatment, the second etching treatment and the seconddoping treatment follow in this order. However, apparently, the order ofthe treatment is not limited thereto. For example, the first etchingtreatment may be followed by the second etching treatment, the seconddoping treatment, and the first doping treatment in the order stated, orthe first etching treatment may be followed by the second etchingtreatment, the first doping treatment, and the second doping treatmentin the order stated.

Next, a resist mask is formed for the third doping treatment. The resistmask covers the semiconductor layers that form n-channel TFTs. Throughthe third doping treatment, third impurity regions doped with animpurity element that imparts the p type conductivity are formed in thesemiconductor layers for forming p-channel TFTs and the semiconductorlayers for forming a capacitor storage in the pixel portion and drivingcircuit. The concentration of the impurity element that imparts the ptype conductivity in the third impurity regions is 1×10¹⁸ to 1×10²⁰/cm³.The third impurity regions are already doped with phosphorus (P) in theprevious step but are doped with the impurity element that imparts the ptype conductivity in a concentration large enough to obtain the p typeconductivity. Here, a region having the same concentration range as thethird impurity regions is also called a p⁻ region.

Without removing the above-described resist mask, the fourth dopingtreatment is conducted. Through the fourth doping treatment, fourthimpurity regions doped with an impurity element that imparts the p typeconductivity are formed in the semiconductor layers for formingp-channel TFTs and the semiconductor layers for forming a storagecapacitor in the pixel portion and driving circuit. The concentration ofthe impurity element that imparts the p type conductivity in the fourthimpurity regions is 1×10²⁰ to 1×10²¹/cm³. The fourth impurity regionsare already doped with phosphorus (P) in the previous step but are dopedwith the impurity element that imparts the p type conductivity in aconcentration 1.5 to 3 times the phosphorus concentration to obtain thep type conductivity. Here, a region having the same concentration rangeas the fourth impurity regions is also called a p⁺ region.

Through the above steps, an impurity region having the n type or p typeconductivity is formed in each semiconductor layer. In the pixel portionand driving circuit, p⁻ regions 112 and p⁺ regions 113 are formed in asemiconductor layer that forms a p-channel TFT whereas n⁻ regions 111and n⁺ regions 110 are formed in a semiconductor layer that forms ann-channel TFT.

The next step is activation treatment of the impurity elements used todope the semiconductor layers. The activation step employs rapid thermalannealing (RTA) using a lamp light source, irradiation of a YAG laser orexcimer laser from the back side, or heat treatment using a furnace, ora combination of these methods. Here, an electric furnace is used andheat treatment is conducted in a nitrogen atmosphere at 550° C. for 4hours for the activation treatment.

Next, a first interlayer insulating film 114 is formed to cover almostthe entire surface. The first interlayer insulating film in thisembodiment is a silicon oxide film formed by plasma CVD to have athickness of 50 nm. The first interlayer insulating film is not limitedto a silicon oxide film and a single layer or laminate of otherinsulating films containing silicon may be used.

In the example shown in this embodiment, the first interlayer insulatingfilm is formed after the above-described activation. However, theinsulating film may be formed before the activation.

On the first interlayer insulating film, a silicon nitride filmcontaining hydrogen is formed as a second interlayer insulating film(not shown) to have a thickness of 100 nm. Then, the semiconductorlayers are subjected to heat treatment (at 300 to 550° C. for 1 to 12hours) to hydrogenate the semiconductor layers. This step is forterminating dangling bonds in the semiconductor layers using hydrogencontained in the second interlayer insulating film. The semiconductorlayers are hydrogenated irrespective of the presence of the firstinterlayer insulating film that is a silicon oxide film. Otherhydrogenation methods employable include plasma hydrogenation (usinghydrogen excited by plasma).

Next, a third interlayer insulating film 115 is formed on the secondinterlayer insulating film from an organic insulating material. In thisembodiment, an acrylic resin film is formed to have a thickness of 1.05μm. Formed next are contact holes reaching the conductive layers thatserve as the gate electrodes or gate wires and contact holes reachingthe impurity regions. In this embodiment, etching treatment is conductedseveral times in succession. Also, in this embodiment, the secondinterlayer insulating film is used as an etching stopper to etch thethird interlayer insulating film, then the first interlayer insulatingfilm is used as an etching stopper to etch the second interlayerinsulating film, and then the first interlayer insulating film isetched.

Thereafter, electrodes 116 to 122, specifically, a source wire, a powersupply line, a lead-out electrode, a connection electrode, etc. areformed from Al, Ti, Mo, or W. Here, the electrodes and wires areobtained by patterning a laminate of a Ti film (100 nm in thickness), anAl film containing silicon (350 nm in thickness), and another Ti film(50 nm in thickness). The source electrode, source wire, connectionelectrode, lead-out electrode, power supply line, and the like are thusformed as needed. A lead-out electrode for the contact with a gate wirecovered with an interlayer insulating film is provided at an end of thegate wire, and other wires also have at their ends input/output terminalportions having a plurality of electrodes for connecting to externalcircuits and external power supplies.

A driving circuit 202 having a CMOS circuit in which an n-channel TFT205 and a p-channel TFT 206 are combined complementarily and a pixelportion 201 with a plurality of pixels each having an n-channel TFT 203or a p-channel TFT 204 are formed in the manner described above.

In the driving circuit, the semiconductor layer of the n-channel TFT (afirst n-channel TFT) 205 has: a channel formation region, the secondimpurity regions (n⁻ regions) 111 partially overlapping the conductivelayer that forms the gate electrode with an insulating film sandwichedbetween the region and the layer; and the first impurity regions (n⁺regions) 110 one of which functions as a source region and the other ofwhich functions as a drain region.

In the driving circuit, the semiconductor layer of the p-channel TFT (afirst p-channel TFT) 206 has: a channel formation region, the thirdimpurity regions (p⁻ regions) 112 partially overlapping the conductivelayer that forms the gate electrode with an insulating film sandwichedbetween the region and the layer; and the fourth impurity regions (p⁺regions) 113 one of which functions as a source region and the other ofwhich functions as a drain region.

Combinations of these TFTs (the first n-channel TFT and the firstp-channel TFT) are appropriately used to form a shift register circuit,a buffer circuit, a level shifter circuit, a latch circuit, and the liketo constitute the driving circuit.

In the pixel portion 201, namely, the whole region where a large numberof pixels are arranged to form a matrix, each pixel has a plurality ofn-channel TFTs or p-channel TFTs. These TFTs can be roughly divided intoTFTs that are electrically connected to OLEDs formed in a later step andother TFTs. The TFTs electrically connected to OLEDs formed in a laterstep (also called current controlling TFTs) control a current flowinginto the OLEDs and may either be n-channel TFTs or p-channel TFTs. A TFTelectrically connected to an OLED formed in a later step in thisembodiment, is a p-channel TFT (a second p-channel TFT) 204. In thisembodiment, each pixel has one TFT other than the second p-channel TFTand has an n-channel TFT (a second n-channel TFT) 203 as a switchingTFT. A drain region of the second n-channel TFT is connected to a gateelectrode of the second p-channel TFT through a connection electrode. Aconnection electrode 122 electrically connected to an anode or cathodeof an OLED to be formed later is formed in a drain region of the secondp-channel TFT.

The electrodes are patterned and then the resist is removed for heattreatment at 150° C. for 12 minutes. Next, a pixel electrode 123 isformed such that it is in contact with and overlaps the connectionelectrode that is in contact with the drain region of the secondp-channel TFT. In this embodiment, the pixel electrode functions as ananode of an OLED and light emitted from the OLED passes through thepixel electrode. Therefore, a transparent conductive film is used forthe pixel electrode. A conductive film having a large work function,typically a conductive oxide film is used for the anode. The conductiveoxide film is formed from indium oxide, tin oxide, or zinc oxide, or acompound of those. The pixel electrode in this embodiment is obtained byforming an ITO (an alloy of indium oxide and tin oxide) that is atransparent conductive film by sputtering to have a thickness of 110 nmand patterning it in the pixel portion to form a matrix pattern and havea desired shape. Examples of other transparent conductive films that canbe employed include an indium oxide-zinc oxide alloy (In₂O₃—ZnO) filmand a zinc oxide (ZnO) film. At the same time the pixel electrode isformed, electrode pads may be formed from the transparent conductivefilm and patterned so that they are in contact with and overlap theelectrodes of the input/output terminal portions.

After finishing patterning the pixel electrode, the resist is removedfor heat treatment at 250° C. for an hour.

FIG. 4 shows the device that has finished the manufacture process upthrough the steps described above. Electric measurement on the TFTsformed on the first substrate 101 is conducted at this point. The V-Icharacteristic graph of the n-channel TFT with the ratio of the channelwidth W to the channel length L set to 50 μm: 50 μm is shown in FIG. 9.FIG. 10 shows the V-I characteristic graph of the p-channel TFT with theratio of the channel width W to the channel length L set to 50 μm:50 μm.

Next, an insulator called a bank is formed on each end of the pixelelectrode 123 so as to cover each end of 123. The bank is formed from aninsulating film containing silicon or a resin film. In this embodiment,a photo-sensitive acrylic resin film is 0 formed to have a thickness of1 μm and is patterned into a desired shape. Then, heat treatment isconducted at 250° C. for an hour.

A highly rigid substrate (a second substrate), here a quartz substratewith a thickness of 1.1 mm, is next prepared and is bonded to the sideon which the TFTs are formed using an adhesive soluble in a solvent (afirst bonding member) or a photosensitive adhesive (a first bondingmember) that is reduced in adhesion when irradiated with light(including ultraviolet rays). The TFTs are thus sandwiched between thequartz substrate (the second substrate) and the glass substrate (thefirst substrate). The use of a highly rigid substrate prevents crackingin the layer including the TFTs during a later peeling step. In thisembodiment, an adhesive soluble in water is used as the first bondingmember. Examples of other usable adhesive include an adhesive soluble inan alcoholic-based organic solvent and a photosensitive adhesive. Beforebonding the substrates, it is important to provide an initiator thatfacilitates the peeling phenomenon during a later peeling step. Byselectively (partially) lowering the adhesion as preprocessing, peelingfailure is avoided and the yield is improved. The preprocessing consistsof, for example, laser light scanning or scratching of the thin filmwhile a needle vertically depresses the thin film to apply a load andthe film is moved along the perimeter of the region to be peeled. Inthis embodiment, a scriber apparatus is used and the depression amountis set to 0.1 to 2 mm to scratch the thin film at a pressure of 0.5kg/cm².

Desirably, the peeling is started from an area near the region subjectedto the preprocessing.

Next, the first substrate on which the first material layer (tungstenfilm) is formed is pulled off by a physical measure. Thus, the layerincluding the TFTs is transferred onto the second substrate and thesurface exposed is the second material layer (silicon oxide film formedby sputtering). The adhesion between the first material layer and thesecond material layer is strong enough to withstand the heat treatmenttemperature but is very weak against a mechanical force. Therefore, thefirst substrate can be pulled off with a relatively small force (forexample, by hands, pressure of a gas sprayed through a nozzle,supersonic, or the like). Since the adhesion is weakened in part by theabove-described preprocessing, it requires an even smaller force to pullthe first substrate off.

If giving the first substrate and the second substrate the same sizemakes works difficult, the second substrate can be slightly smaller insize than the first substrate. If a plurality of pixel portions areformed on one sheet of the first substrate, the first substrate may becut into pieces so that each piece has one pixel portion.

Next, a third substrate is bonded to the exposed second material layerusing the second bonding member to sandwich the TFTs between the quartzsubstrate (the second substrate) and the third substrate. Any substratecan be used as the third substrate.

The second bonding member is an adhesive composed of a UV-curable epoxyresin which is not water-soluble. A (0.3 mm thick) polycarbonate (PC)film with an AlN_(X)O_(Y) film formed on the surface is used as thethird substrate. It is preferable to choose for the second bondingmember a material whose adhesion to the second material layer isstronger than at least its adhesion to the AlN_(X)O_(Y) film. This waythe third substrate can be peeled in a later step so that the secondbonding member alone serves as a supporter.

As the device finishes the manufacture process up through the abovesteps, a micrometer is used to measure the total thickness of the layersandwiched between the second substrate (1.1 mm) and the third substrate(0.3 mm) (the total thickness including the thickness of the pair ofsubstrates). The measured thickness thereof is 1.6 to 1.9 mm.

The pair of substrates sandwiching the TFTs are completely immersed in atank filled with water to dissolve the water-soluble bonding member (thefirst bonding member) and peel the second substrate off. The dissolutionspeed of the water-soluble bonding member (the first bonding member) maybe increased by supersonic or irradiation of laser light. At the sametime, immersion in water separates the third substrate from the secondbonding member at the interface to peel the third substrate off.Although the second substrate and the third substrate are peeled in thesame step, they may be peeled in different steps.

The peeling is followed by heat treatment for vaporizing moisture.Treatment for thoroughly removing the water-soluble bonding member (thefirst bonding member) may be conducted after the second substrate ispeeled off.

Thus obtained is the layer including the TFTs with the second bondingmember alone serving as a supporter. At this stage, the electricmeasurement of the TFTs is again conducted. The V-I characteristic graphof the n-channel TFT with the ratio of the channel width W to thechannel length L set to 50 μm:50 μm is shown in FIG. 11. FIG. 12 showsthe V-I characteristic graph of the p-channel TFT with the ratio of thechannel width W to the channel length L set to 50 μm 50 μm.

As can be read from FIGS. 9 to 12, there is almost no change in TFTcharacteristic. Accordingly, it can be said that transferring andpasting done by following these procedures do not affect the TFTs.Although the TFTs may be formed directly on a plastic substrate, the lowheat resistance of the substrate makes heat treatment at 300° C. orhigher difficult to conduct as well as forming TFTs having as excellentcharacteristic as the one in FIGS. 9 to 12. By forming TFTs on aheat-resistant substrate and then peeling the heat-resistant substrateoff as shown in this embodiment, TFTs having as excellent characteristicas the one in FIG. 9 to 12 can be obtained.

As the device finishes the manufacture process up through the abovesteps, a micrometer is used to measure the total thickness (includingthe thickness of the second bonding member) of the layer including theTFTs and using the second bonding member alone as a supporter. Themeasured thickness thereof is 140 to 230 μm. As proved by this, totalthickness can be thinner than a PC film (0.3 mm). Since the TFTcharacteristic can be measured despite being this thin, it can be saidthat the second bonding member makes a sufficient supporter by itselfand the device can be driven as a semiconductor device.

Next, an EL layer is formed on the pixel electrode whose ends arecovered by the banks and a cathode of an OLED is formed thereon.

An EL layer (a layer for light emission and for moving of carriers tocause light emission) has a light emitting layer and a free combinationof electric charge transporting layers and electric charge injectionlayers. For example, a low molecular weight organic EL material or ahigh molecular weight organic EL material is used to form an EL layer.An EL layer may be a thin film formed of a light emitting material thatemits light by singlet excitation (fluorescence) (a singlet compound) ora thin film formed of a light emitting material that emits light bytriplet excitation (phosphorescence) (a triplet compound). Inorganicmaterials such as silicon carbide may be used for the electric chargetransporting layers and electric charge injection layers. Known organicEL materials and inorganic materials can be employed.

It is said that the preferred material of a cathode is a metal having asmall work function (typically, a metal element belonging to Group 1 or2 in the periodic table) or an alloy of such metal. The light emissionefficiency is improved as the work function becomes smaller. Therefore,an alloy material containing Li (lithium) that is one of alkali metalsis particularly desirable as the cathode material. The cathode alsofunctions as a wire common to all pixels and has a terminal electrode inan input terminal portion through a connection wire.

Next, the OLED having at least a cathode, an organic compound layer, andan anode is preferably sealed by an organic resin, a protective film, asealing substrate, or a sealing can to cut the OLED completely off fromthe outside and prevent permeation of external substances, such asmoisture and oxygen, that accelerate degradation due to oxidization ofthe EL layer. However, it is not necessary to provide the protectivefilm or the like in the input/output terminal portions to which an FPCneeds to be connected later.

The FPC (flexible printed circuit) is attached to the electrodes of theinput/output terminal portions using an anisotropic conductive material.The anisotropic conductive material is composed of a resin andconductive particles several tens to several hundreds μm in diameterwhose surfaces are plated by Au or the like. The conductive particleselectrically connect the electrodes of the input/output terminalportions with wires formed in the FPC.

If necessary, an optical film such as a circularly polarizing platecomposed of a polarizing plate and a phase difference plate may beprovided and an IC chip may be mounted.

Through the above steps, a module type light emitting device to which anFPC is connected is completed. In the light emitting device of thisembodiment, light emitted from an OLED passes through the second bondingmember alone to reach the eyes of an observer. Therefore, the secondbonding member is desirably formed from a light-transmissive material.

Alternatively, the pixel electrode may serve as a cathode and an ELlayer and an anode may be layered on the cathode so that light isemitted in the direction opposite to the light emitting direction inthis embodiment. In this case, the anode is formed from alight-transmissive material.

In the example shown in this embodiment, the OLED is formed after themanufacture is advanced to a point where the second bonding member aloneserves as a supporter. However, the OLED may be sealed prior to peelingthe first substrate off, and then the second substrate may be bonded,the first substrate may be peeled off, the third substrate may bebonded, and the second substrate and the third substrate may be peeledoff. In the case where the substrate is peeled off after the OLED isformed, it is preferable to use an organic solvent as the solvent andemploy an adhesive soluble in an organic solvent instead of using wateras the solvent and employing a water-soluble adhesive.

If the second bonding member is chosen properly when forming the OLEDprecedes peeling of the substrate, it is possible to peel the secondsubstrate alone while leaving the third substrate in place. In thiscase, a light emitting device having an OLED can be formed on a plasticsubstrate.

Embodiment 2

In this embodiment, an example of manufacturing the light emittingdevice having OLED by the step that differs from Embodiment 1 in part.

According to Embodiment 1, state of complete the first etching processis obtained. Although in Embodiment 1, the first doping process, thesecond etching process, and the second doping process are performed inthis order after the first etching process is performed. However, inthis embodiment, the second etching process is performed after the firstetching process is performed. And after removing the resist mask, lowdensity doping is performed by new doping process to form the fifthimpurity region (n⁻⁻ region). Subsequently, new resist mask is formed,and doping is selectively performed using same dose amount as the seconddoping process, thereby doping is performed using same dose amount asthe first doping process.

TFT formed by steps of this embodiment is described with reference toFIG. 5.

In this embodiment, the fifth impurity region (n⁻⁻ region) is formed byperforming low density doping by new doping process. The gate electrodes305 to 308 are used as masks to perform doping with whole surface. Asdoping process may be used ion doping or ion injecting. The condition ofion doping process is that dose amount is 1.5×10¹⁴ atoms/cm² and theaccelerate voltage is 60 to 100 keV. As impurity elements imparting ann-type may be used phosphor (P), or arsenic (As). The fifth impurityelement region is formed in a self-alignment manner. The n-type impurityelement is added to the fifth impurity region at 1×10¹⁶ to 1×10¹⁷/cm³.In this embodiment, the same density region as the fifth impurity regionis referred to as n⁻⁻ region.

Subsequently, new resist mask is formed. In this case, since OFF currentvalue of the switching TFT 403 is lowered, the mask is formed to coverthe channel formation region of the semiconductor layer that forms theswitching TFT 403 of the pixel portion 401 or the part. In addition, themask is formed to protect the channel formation region of thesemiconductor layer that forms the p-channel TFT 406 of the drivercircuit or the periphery region thereof. Further, the mask is formed tocover the channel formation region of the semiconductor layer that formsthe current control TFT 404 of the pixel portion 401 and the peripheryregion thereof.

The second impurity region 311 that overlaps with a part of the gateelectrode 305 by doping selectively by using same dose amount as thesecond doping process using above-mentioned resist masks.

Without removing the above-mentioned resist masks, doping is selectivelyperformed by using the same dose amount as the first doping process toform the first impurity regions 312 and 315. At the switching TFT 403,the region covered with resist becomes the fifth impurity region 316.

In the above-mentioned steps, doping is performed to the semiconductorlayer that is to be an activation layer of the n-channel TFT.

Next, after removing the above-mentioned resist masks, as Embodiment 1,the resist mask is formed, and the third and fourth doping processes areperformed continuously.

In the above-mentioned steps, n-type or p-type conductive type impurityregion is formed on each semiconductor layer. At the pixel portion 401and the driver circuit 402, p⁻ regions 314, 318, p⁺ regions 313 and 317are formed on the semiconductor layer that forms the p-channel type TFT,n⁻ region 311 and n+region 312 are formed on the semiconductor layerthat forms n-channel TFT of the driver circuit 402, and n⁺ region 315and n⁻ region 316 are formed on the semiconductor layer that formsn-channel type TFT of the pixel portion 401, respectively.

According to Embodiment 1, an activation process of the impurityelements added to each semiconductor layer is performed. Next, theformation process of the first interlayer insulating film 309, theformation process of the second interlayer insulating process (notillustrated), the hydrogenation process of the semiconductor layer, andthe formation process of the third interlayer insulating film 310 areperformed according to Embodiment 1.

The pixel electrode 319 contacting to overlap with the connectionelectrode 326 formed later. The connection electrode contacts to thedrain region of the current control TFT consisted of p-channel TFT. Inthis embodiment, the pixel electrode functions as an anode of the OLED,and is transparent conductive film to pass the light from the OLED tothe pixel electrode.

Next, contact hole that reaches to the gate electrode or the conductivelayer that is to be the gate wiring and the contact hole that reaches toeach impurity region. The plural etching processes are performedsequentially in this embodiment. After the third interlayer insulatingfilm is etched by using the second interlayer insulating film as anetching stopper, the second interlayer insulating film is etched byusing the first interlayer insulating film as an etching stopper,thereby the first interlayer insulating film is etched.

After that, the electrodes 320 to 326, specifically, a source wiring, acurrent supply line, a drawing electrode, and connection electrode areformed by using Al, Ti, Mo, W, and the like. In this embodiment, as thematerial for these electrodes and wirings may be used a laminationstructure consisted of Ti film (having a thickness of 100 nm), Al filmcontaining silicon (having a thickness of 350 nm), and Ti film (having athickness of 50 nm), and the patterning is performed. Thus, the sourceelectrode or source wiring, the connection electrode, the drawingelectrode, the power source supply line, and the like are formedappropriately. The drawing electrode for contacting the gate wiring thatis covered by the interlayer insulating film is formed at the peripheryof the gate wiring. The input-output terminal portions in which theelectrode for connecting the external circuit or the external powersource is formed are formed at another periphery portion of each wiring.The connection electrode 326 that is formed to contact and overlap withthe pixel electrode 319 formed previously is contacting the drain regionof the current control TFT 404.

As mentioned above, the driver circuit having the n-channel TFT 405having the p-channel TFT 406, and CMOS circuit that is formed bycombining complementary these TFTs, and the pixel portion 401 havingn-channel TFT 403 or the p-channel TFT 404 in plurality in a pixel canbe formed.

When the patterning is completed, heat treatment is performed byremoving resists as Embodiment 1, subsequently, the insulator 327referred to as bank is formed to cover the edge portion of the pixelelectrode 319 at both end sides. The bank may be formed by theinsulating film or the resin film.

According to Embodiment Mode 1 or 2, a layer containing TFT in which thebonding member 300 that contacts the second material layer 310 is usedas a support medium may be obtained.

Next, the EL layer 328 and the cathode 329 of OLED are formed on thepixel electrode that the edge portions thereof are covered by bankaccording to Embodiment 1.

The state up through this step is illustrated in FIG. 5.

The following steps is that OLED is cut off from the outside by sealingOLED having at least the cathode, the organic compound layer, and theanode using an organic resin, a protective film, a sealing substrate, ora sealing can. Thereby it is prevent materials such as water and oxygenthat deteriorates EL layer from penetrating into OLED by cutting offOLED completely from outside.

Next, FPC (Flexible Printed Circuit) is stuck to each electrode ofinput-output terminal portions by using anisotropic conductivematerials.

By above-mentioned steps, the module type light emitting deviceconnecting FPC is completed. In the light emitting device of thisembodiment, light emitted from OLED passing through only the secondbonding member can be seen by viewer. Therefore, it is preferable thatthe material having light transmitting property is used for the secondbonding member.

Embodiment 3

The top surface view and the cross-sectional view of the module typelight emitting device (also referred to as EL module) obtained byEmbodiment 1 or 2 are shown.

FIG. 6A is a view of a top surface view of EL module and FIG. 6B is across-sectional view taken along the line of A-A′ of FIG. 6A. FIG. 6Ashows that the base insulating film 501 is formed on the bonding member500 (for example, the second bonding member and the like), and the pixelportion 502, the source side driver circuit 504, and the gate sidedriver circuit 503 are formed thereon. These pixel portion and drivercircuit may be obtained according to above-mentioned Embodiment 1 or 2.

The reference numeral 518 is an organic resin and 519 is a protectivefilm. The pixel portion and the driver circuit portion are covered bythe organic resin 518, and the organic resin 518 is covered by theprotective film 519. In addition, the organic resin may be sealed by thecover material using the bonding member. The cover material can beadhered as a support medium before peeling-off is subjected.

In addition, reference numeral 508 represents a wiring for transmittingsignals to be inputted into the source side driving circuit 504 and thegate side driving circuit 503, and it receives a video signal and aclock signal from the FPC (flexible print circuit) 509 which becomes anexternal input terminal. In addition, here, only FPC is shown in thefigure, but a printed wiring board (PWB) may be attached to this FPC. Alight emitting device in the present specification is assumed to containnot only a light emitting device itself but also a state in which FPC orPWB is attached thereto.

The cross-sectional structure shown in FIG. 6B is described. A baseinsulating film 501 is formed on the bonding member 500. The pixelportion 502 and the gate driving circuit 503 are formed above theinsulating film 501. The pixel portion 502 is composed of the currentcontrol TFT 511 and plural pixels including the pixel electrode 512 thatis connected electrically to the drain of the current control TFT 511.In addition, the gate driving circuit 503 is formed by using a CMOScircuit that is combined with the n-channel TFT 513 and the p-channelTFT 514.

The TFTs (including 511, 513, and 514) may be manufactured according ton-channel TFT of Embodiment 1 and p-channel TFT of Embodiment 1.

After that the pixel portion 502, the source side driver circuit 504,and the gate side driver circuit 503 are formed on the same substrateaccording to Embodiment 2, only the bonding member 500 is used as asupport medium according to Embodiment Mode 1 or 2.

The pixel electrode 512 functions as an anode of the light emittingelement (OLED). The bank 515 is formed at the both ends portion of thepixel electrode 512. An organic compound layer 516 and a cathode 517 ofthe light emitting element are formed on the pixel electrode 512.

As the organic compound layer 516, it should be appreciated that theorganic compound layer (a layer for carrying out light emission andmovement of carriers therefore) may be formed by freely combining alight emitting layer, an electric charge transport layer or an electriccharge injection layer. For example, low molecular series organiccompound material and high molecular series organic compound materialmay be used. Further, as the organic compound layer 516, a thin filmwhich comprises a light emitting material (singlet compound) which emitslight by singlet excitation, or a thin film which comprises a lightemitting material (triplet compound) which emits light (phosphorouslight) by triplet excitation may be used. Furthermore, it is possible touse an inorganic material such as silicon carbide as the electric chargetransport layer and the electric charge injection layer. As theseorganic and inorganic materials, well-know materials can be used.

The cathode 517 functions as a common wiring to all pixels, and iselectrically connected to an FPC 509 through a connection wiring 508.Further, elements which are contained in the pixel portion 502 and thegate side driving circuit 503 are all covered by the cathode 517, anorganic resin 518 and a protective film 519.

In addition, as the organic resin 518, it is preferable to use atransparent or half transparent material to visible light to the extentpossible. Further, it is preferable that the organic resin 518 is amaterial which does not transmit impurities such as moisture and oxygento the extent possible.

Also, it is preferred that after the light emitting element has beencompletely covered with the organic resin 518, the protective film 519be at least formed on the surface (exposed surface) of the organic resin518 as shown in FIGS. 6A and 6B. The protective film may be formed onthe entire surface including the back surface of the substrate. In sucha case, it is necessary to carefully form the protective film so that noprotective film portion is formed at the position where the externalinput terminal (FPC) is provided. A mask may be used to prevent filmforming of the protective film at this position. The external inputterminal portion may be covered with a tape such as a tape made ofTeflon (registered trademark) used as a masking tape in a CVD apparatusto prevent film forming of the protective film. The silicon nitridefilm, the DLC film, or AlN_(X)O_(Y) film may be used as the protectivefilm 519.

The light emitting element constructed as described above is enclosedwith the protective film 519 to completely isolate the light emittingelement from the outside, thus preventing materials such as water andoxygen which accelerate degradation of the organic compound layer byoxidation from entering from the outside. Also, the film having thermalconductivity enables dissipation of produced heat. Thus, the lightemitting device having improved reliability is obtained.

Another arrangement is conceivable in which a pixel electrode is used asa cathode, and an organic compound layer and an anode are formed incombination to emit light in a direction opposite to the directionindicated in FIG. 6B. FIG. 7 shows an example of such an arrangement.The top view thereof is the same as the top view shown in FIG. 6A andwill therefore be described with reference to a cross-sectional viewonly.

The structure shown in the cross-sectional view of FIG. 7 will bedescribed. An insulating film 610 is formed on a bonding member 600, anda pixel portion 602 and a gate-side drive circuit 603 are formed abovethe insulating film 610. The pixel portion 602 is formed by a pluralityof pixels including a current control TFT 611 and a pixel electrode 612electrically connected to the drain of the current control TFT 611. Inaddition, only the bonding member 600 is used as a support mediumaccording to Embodiment Mode. A gate side driver circuit 603 is formedby using a CMOS circuit having a combination of an n-channel TET 613 anda p-channel TFT 614.

These TFTs (611, 613, 614, etc.) may be fabricated in the same manner asthe n-channel TFT of Embodiment 1 and the p-channel TFT of Embodiment 1.

The pixel electrode 612 functions as a cathode of the light emittingelement (OLED). Banks 615 are formed at opposite ends of the pixelelectrode 612, and an organic compound layer 616 and an anode 617 of thelight emitting element are formed over the pixel electrode 612.

The anode 617 also functions as a common wiring element connected to allthe pixels and is electrically connected to a FPC 609 via connectionwiring 608. All the elements included in the pixel portion 602 and thegate-side drive circuit 603 are covered with the cathode 617, an organicresin 618 and a protective film 619. A cover member 620 is bonded to theelement layer by an adhesive. A recess is formed in the cover member anda desiccant 621 is set therein.

In the arrangement shown in FIG. 7, the pixel electrode is used as thecathode while the organic compound layer and the anode are formed incombination, so that light is emitted in the direction of the arrow inFIG. 7.

While the top gate TFTs have been described by way of example, thepresent invention can be applied irrespective of the TFT structure. Forexample, the present invention can be applied to bottom gate (invertedstaggered structure) TFTs and staggered structure TFTs.

Embodiment 4

This embodiment is an example of a half-transmission type of displaydevice in which pixel electrodes are formed of an conductive film havinga light-transmitting property and a metallic material having areflecting property, as shown in FIG. 8.

In a liquid crystal display device, an n-channel TFT that functionspixel electrodes can be formed according to Embodiment 1 or 2. The stepof forming the interlayer insulating layer covering the TFTs and thesteps performed before this step are the same as those in Embodiment 1,and the description for them will not be repeated. One of two electrodesin contact with the source region or the drain region of a TFT is formedof a metallic material having a reflecting property to form a pixelelectrode (reflecting portion) 702. Subsequently, a pixel electrode(transmitting portion) 701 made of a conductive film having alight-transmitting property is formed so as to overlap the pixelelectrode (reflecting portion) 702. As the conductive film having alight-transmitting property, indium-tin oxide (ITO), indium-zinc oxide(In₂O₂—ZnO) or zinc oxide (ZnO), for example, may be used.

The pixel TFT is formed on the first substrate as mentioned steps. Afterthe first substrate is peeled off according to Embodiment Mode 1 or 2, alayer containing TFT in which only the bonding member 700 functions as asupport medium.

An alignment film is formed and subjected to rubbing treatment. In thisembodiment, before the alignment film is formed, an organic resin filmsuch as an acrylic resin film is patterned to form columnar spacers (notillustrated) in desired positions in order to keep the substrates apart.The columnar spacers may be replaced by spherical spacers sprayed ontothe entire surface of the substrate.

An opposite substrate functioning as a support medium is prepared next.The opposite substrate has a color filter (not illustrated) in whichcolored layers and light-shielding layers are arranged with respect tothe pixels. A light-shielding layer is also placed in the drivingcircuit portion. A planarization film is formed to cover the colorfilter and the light-shielding layer. On the planarization film, anopposite electrode is formed from a transparent conductive film in thepixel portion. An alignment film is formed over the entire surface ofthe opposite substrate and is subjected to rubbing treatment.

The bonding member 700 in which the pixel portion and the driver circuitare formed and the opposite substrate are adhered together by thesealing material. Into a sealing material, filler is mixed, two sheetsof substrates are adhered together with uniform interval by this fillerand a spacer in a column shape. Then, between both substrates, a liquidcrystal material is implanted and completely sealed with a sealingcompound (not shown). A backlight 704 and a light guide plate 705 areprovided on the obtained liquid crystal module. The liquid crystalmodule is thereafter covered with a cover 706. An active-matrix liquidcrystal display device such as that partially shown in section in FIG. 8is thereby completed. The cover and the liquid crystal module are bondedto each other by using an adhesive and an organic resin. When theplastic substrate and the opposed substrate are bonded to each other, aspace between the opposed substrate and a frame placed so as to surroundthe opposed substrate may be filled with the organic resin for bonding.Since the display device is of a half-transmission type, polarizingplates 703 are adhered to both the bonding member 700 and the opposedsubstrate.

When a sufficient quantity of external light is supplied, the displaydevice is driven as a reflection type in such a manner that while thebacklight is maintained in the off state, display is performed bycontrolling the liquid crystal between the counter electrode provided onthe opposed substrate and the pixel electrodes (reflecting portions)702. When the quantity of external light is insufficient, the backlightis turned on and display is performed by controlling the liquid crystalbetween the counter electrode provided on the opposed substrate and thepixel electrodes (transmitting portions) 701.

However, if the liquid crystal used is a TN liquid crystal or an STNliquid crystal, the twist angle of the liquid crystal is changed betweenthe reflection type and the transmission type. Therefore, there is aneed to optimize the polarizing plate and the phase difference plate.For example, a need arises to separately provide an optical rotationcompensation mechanism for adjusting the twist angle of the liquidcrystal (e.g., a polarizing plate using a high-molecular weight liquidcrystal).

Embodiment 5

The driver circuit and the pixel portion formed by implementing thepresent invention can be used to various modules (active matrix liquidcrystal module, active matrix EL module and active matrix EC module).Namely, all of the electronic equipments are completed by implementingthe present invention.

Following can be given as such electronic equipments: video cameras;digital cameras; head mounted displays (goggle type displays); carnavigation systems; projectors; car stereos; personal computers;portable information terminals (mobile computers, mobile phones orelectronic books etc.) etc. Examples of these are shown in FIGS. 13 to15.

FIG. 13A is a personal computer which comprises: a main body 2001; animage input section 2002; a display section 2003; and a keyboard 2004etc.

FIG. 13B is a video camera which comprises: a main body 2101; a displaysection 2102; a voice input section 2103; operation switches 2104; abattery 2105 and an image receiving section 2106 etc.

FIG. 13C is a mobile computer which comprises: a main body 2201; acamera section 2202; an image receiving section 2203; operation switches2204 and a display section 2205 etc.

FIG. 13D is a goggle type display which comprises: a main body 2301; adisplay section 2302; and an arm section 2303 etc.

FIG. 13E is a player using a recording medium in which a program isrecorded (hereinafter referred to as a recording medium) whichcomprises: a main body 2401; a display section 2402; a speaker section2403; a recording medium 2404; and operation switches 2405 etc. Thisapparatus uses DVD (digital versatile disc), CD, etc. for the recordingmedium, and can perform music appreciation, film appreciation, games anduse for Internet.

FIG. 13F is a digital camera which comprises: a main body 2501; adisplay section 2502; a view finder 2503; operation switches 2504; andan image receiving section (not shown in the figure) etc.

FIG. 14 is a figure showing a driver's seat area. The sound reproductiondevice, specifically, a car audio and a car navigation are provided in adash board. A main body 2701 of the car audio comprises; the displayportion 2702, operation switches 2703 and 2704. By applying the presentinvention to the display portion 2702, thin and light-weight car audiocan be obtained. And by applying the present invention to the displayportion 2801 of the car navigation system, thin and light-weight carnavigation system can be obtained.

In an operation handle portion 2602, the display portion 2603 thatdigitally displays of the speed meter instruments is formed in thedashboard 2601. by applying the present invention to the display portion2702, thin and light-weight display device of machines can be obtained.

In addition, a display portion 2605 pasted on the curved face of thedashboard portion 2601 may be formed. By applying the present inventionto the display portion 2605, thin and light-weight display portion ofmachines or image display device can be obtained.

Further, the display portion 2600 pasted on the curved face of the frontglass 2604 may be formed. In the case that the present invention isapplied to the display portion 2600, materials having light transmittingproperty may be used. Thin and light-weight display device of machinesor image display device can be obtained. In this embodiment, though thefront glass is used, another window glass can be obtained.

In this embodiment, although a car mounted audio and a car navigationare shown, this embodiment can be used to another display device orfixed type audio and navigation device.

FIG. 15A is a mobile phone which comprises: a main body 2901; a voiceoutput section 2902; a voice input section 2903; a display portion 2904;operation switches 2905; an antenna 2906; and an image input section(CCD, image sensor, etc.) 2907 etc.

FIG. 15B is a portable book (electronic book) which comprises: a mainbody 3001; display portions 3002 and 3003; a recording medium 3004;operation switches 3005 and an antenna 3006 etc.

FIG. 15C is a display which comprises: a main body 3101; a supportingsection 3102; and a display portion 3103 etc.

In addition, the display shown in FIG. 15C has small and medium-sized orlarge-sized screen, for example a size of 5 to 20 inches. Further, tomanufacture the display part with such sizes, it is preferable tomass-produce by gang printing by using a substrate with one meter on aside.

As described above, the applicable range of the present invention isextremely large, and the invention can be applied to electronicequipments of various areas. Note that the electronic devices of thisembodiment can be achieved by utilizing any combination of constitutionsin Embodiments 1 to 4.

Embodiment 6

In this embodiment, an example of using an electrophoresis displaydevice as display portions illustrated in Embodiment 5. Typically, theelectrophoresis display device is applied to a display portion 3002 or adisplay portion 3003 of a portable book (electronic book) shown in FIG.15B.

The electrophoresis display device is also referred to as an electronicpaper. It has advantages of readability that is the same as papers, alow power consumption in comparison with other display devices, andshape of thin and light.

The electrophoresis display device can takes a various forms such asthat the plural micro capsules containing the first particle with pluselectric charge and the second particle with minus electric charge isdispersed in the solvent or solute. By applying electric field to themicro capsule, particles in the micro capsule is removed inverseddirection each other so that the color of particles gathered one sideare emitted. In addition, the first particle and the second particlecontain dyestuffs. The particles do not remove without electric field.Further, the color of the first particle and the second particle aredifferent each other (including colorless).

Thus, the electrophoresis display device uses so-called dielectricmigration effect that high dielectric invariable materials are moving tohigh electric field region. The electrophoresis display device is notnecessary a reflection plate and a opposite substrate that are necessaryfor a liquid crystal display device so that the thickness and weight arereduced by half.

Dispersed micro capsules in solvent is referred to as an electronic ink.The electronic ink can be printed on a surface of a glass, a plastic, acloth and a paper. Further, a color display is possible by usingparticles having a color filter and a pigment.

An active matrix type display device can be completed by providingappropriately above-mentioned plural micro capsules between twoelectrodes. If an electric field is applied to the micro capsule, thedevice can display images.

The first particle and the second particle in the micro capsule can beformed by one kind of materials or compound materials selected from thefollowing materials; conductive materials, insulating materials,semiconductor materials, magnetism materials, liquid crystal materials,ferroelectric materials, electro luminescent materials, electrochromicmaterials, and magnetic electrophoresis materials.

This embodiment can be freely combined with Embodiment Modes 1 to 3 andEmbodiments 1 to 5.

Embodiment 7

FIGS. 17 and 18 are photographic diagrams of an organic light emittingelement of the active matrix type formed by using the present invention.

FIG. 17 is a photographic diagram showing an external view of a bendedstate of thin organic light emitting module that is formed according toEmbodiment Mode 3. The module shown in FIG. 17 has a structure ofsandwiched by polycarbonate plastic substrates. Between a pair ofplastic substrates, the cathode, the anode, the plural light emittingelements having layers sandwiching organic compounds by the cathode andthe anode, and TFT for driving the light emitting elements are formed.Other substrate is fixed to a base film of TFT (silicon oxide filmformed by sputtering) by adhesive, and another substrate is also fixedto the cathode of the light emitting element by adhesive.

The display region is configured by providing a matrix of the plurallight emitting elements. The driving circuits for driving these lightemitting elements are provided at the periphery of the display device.In this embodiment, the green luminescent light emitting element ismanufactured for displaying the luminescence. FIG. 18 is a display viewof the luminescence.

In this embodiment, a pair of plastic substrates are used to fix thelight emitting element, however, it is not limited thereof. If themechanical strength and sealing of the light emitting element issufficient, either substrate or both substrates are not needed.

This embodiment can be freely combined with any of Embodiment Modes 1 to3 and Embodiments 1 to 6.

According to the present invention, a semiconductor device having anelement (a thin film transistor, a light emitting device with an OLED,an element with liquid crystal, a memory element, a thin film diode, aphotoelectric conversion element of silicon PIN junction, or a siliconresistor element) which is light-weight, flexible (bendable), and thinas a whole is obtained as well as a method of manufacturing thesemiconductor device.

1. A method of manufacturing a semiconductor device, comprising stepsof: forming a peeled layer over a first substrate; bonding a secondsubstrate to the peeled layer using a first bonding member to sandwichthe peeled layer between the first substrate and the second substrate;separating at least the first substrate from the peeled layer; bonding athird substrate to the peeled layer using a second bonding member tosandwich the peeled layer between the second substrate and the thirdsubstrate; and separating at least the second substrate from the peeledlayer.
 2. A method according to claim 1, wherein the peeled layerincludes at least a transistor.
 3. A method according to claim 1,wherein the first bonding member is a photosensitive bonding member. 4.A method according to claim 1, wherein the first bonding member is aphotosensitive bonding member and the second substrate is separated fromthe peeled layer by irradiating the first bonding member with light. 5.A method according to claim 1, wherein the second substrate is separatedfrom the peeled layer by dissolving the first bonding member in asolvent.
 6. A method according to claim 1, wherein the third substrateis separated from the peeled layer.
 7. A method according to claim 1,wherein the second bonding member is a photosensitive bonding member. 8.A method according to claim 1, wherein the second bonding member is aphotosensitive bonding member and the third substrate is separated fromthe peeled layer by irradiating the second bonding member with light. 9.A method according to claim 1, wherein the third substrate is separatedfrom the peeled layer by dissolving the second bonding member in asolvent.
 10. A method according to claim 1, wherein the second bondingmember adheres to the peeled layer at a stronger adhesion than itsadhesion to the third substrate.
 11. A method according to claim 1,wherein the first substrate is one selected from the group consisting ofa glass substrate, a quartz substrate, and a metal substrate.
 12. Amethod according to claim 1, wherein the second substrate is oneselected from the group consisting of a glass substrate, a quartzsubstrate, and a metal substrate.
 13. A method according to claim 1,wherein the third substrate is a plastic substrate.
 14. A methodaccording to claim 1, wherein the third substrate is a plastic film witha film that contains aluminum, oxygen and nitrogen formed on itssurface.
 15. A method of manufacturing a semiconductor device,comprising steps of: forming a peeled layer over a first substrate;bonding a second substrate with a first bonding member interposedtherebetween so as to sandwich the peeled layer between the firstsubstrate and the second substrate; separating at least the firstsubstrate from the peeled layer; bonding a third substrate with a secondbonding member interposed therebetween so as to sandwich the peeledlayer between the second substrate and the third substrate; andseparating at least the second substrate from peeled layer.
 16. A methodaccording to claim 15, wherein the peeled layer includes at least atransistor.
 17. A method according to claim 15, wherein the firstbonding member is a photosensitive bonding member.
 18. A methodaccording to claim 15, wherein the first bonding member is aphotosensitive bonding member and the second substrate is separated fromthe peeled layer by irradiating the first bonding member with light. 19.A method according to claim 15, wherein the second substrate isseparated from the peeled layer by dissolving the first bonding memberin a solvent.
 20. A method according to claim 15, wherein the thirdsubstrate is separated from the peeled layer.
 21. A method according toclaim 15, wherein the second bonding member is a photosensitive bondingmember.
 22. A method according to claim 15, wherein the second bondingmember is a photosensitive bonding member and the third substrate isseparated from the peeled layer by irradiating the second bonding memberwith light.
 23. A method according to claim 15, wherein the thirdsubstrate is separated from the peeled layer by dissolving the secondbonding member in a solvent.
 24. A method according to claim 15, whereinthe second bonding member adheres to the peeled layer at a strongeradhesion than its adhesion to the third substrate.
 25. A methodaccording to claim 15, wherein the first substrate is one selected fromthe group consisting of a glass substrate, a quartz substrate, and ametal substrate.
 26. A method according to claim 15, wherein the secondsubstrate is one selected from the group consisting of a glasssubstrate, a quartz substrate, and a metal substrate.
 27. A methodaccording to claim 15, wherein the third substrate is a plasticsubstrate.
 28. A method according to claim 15, wherein the thirdsubstrate is a plastic film with a film that contains aluminum, oxygenand nitrogen formed on its surface.